This key facts covers Quick Reference - Character Sets within Character Sets for GCSE Computer Science. Revise Character Sets in 3.3 Data Representation for GCSE Computer Science with 15 exam-style questions and 18 flashcards. This topic appears less often, but it can still be a useful differentiator on mixed-topic papers. It is section 10 of 11 in this topic. Use this key facts to connect the idea to the wider topic before moving on to questions and flashcards.
Quick Reference - Character Sets
ASCII Quick Codes:
- Space = 32
- Digits: '0'=48 to '9'=57
- Uppercase: 'A'=65 to 'Z'=90
- Lowercase: 'a'=97 to 'z'=122
- Lowercase = Uppercase + 32
Character Set Evolution:
- 1960s: ASCII invented (128 characters, English)
- 1980s: Extended ASCII (256 characters, regional)
- 1991: Unicode created (universal standard)
- Today: UTF-8 dominates (95% of web pages)
Why Unicode Won:
- One standard for ALL languages (no more code pages!)
- Backward compatible with ASCII
- Emoji support 😀
- UTF-8 is efficient for English while supporting everything
Practice questions for Character Sets
How many bits does standard ASCII use to represent each character?
Explain why using Unicode to store a text file produces a larger file than using ASCII to store the same text.